In an evolved universal terrestrial radio access (referred to as E-UTRA) system of a 3th Generation Partner Project (referred to as 3GPP), data sending/receiving supports a Hybrid Automatic Repeat Request (referred to as HARQ) technology, to reduce data transmission delay and to obtain a higher data transmission rate. In the HARQ technology, a data receiver needs to feed back acknowledgement/non-acknowledgement (referred to as ACK/NACK) information to a data sender, so as to help the data sender to confirm that the data receiver receives correctly.
In a downlink direction of a 3GPP E-UTRA system, a NodeB (such as, an eNodeB) feeds back the ACK/NACK information corresponding to the uplink data to a user equipment (referred to as UE) via a downlink physical hybrid ARQ indicator channel (referred to as PHICH), i.e. the NodeB (such as, the eNodeB) sends the ACK/NACK information to the UE regarding whether a data transmission block from the UE is received correctly thereby.
Transmission of an LTE physical layer PHICH is organized in form of a PHICH group; multiple PHICHs within one PHICH group occupy the same time-frequency domain physical resources, and adopt a multiplexing manner of an orthogonal spread sequence. In a case of a normal cyclic prefix (referred to as Normal CP), a multiplexing manner that a spreading factor is 4 combined with two paths I/Q of BPSK modulation is adopted; and one PHICH group comprises 12 modulation symbols, occupies three resource element groups (referred to as REG), and multiplexes eight PHICHs. When it is an extended cyclic prefix (referred to as Extended CP), with regard to a radio channel with stronger frequency selectivity, a multiplexing manner that a spreading factor is 2 combined with two paths I/Q of BPSK modulation is adopted; one PHICH group comprises six pieces of modulation multiplexing, and multiplexes four PHICHs; and in this case, two PHICH groups jointly occupy physical resources of three REGs.
One PHICH is jointly determined by ID (nPHICHgroup) of the PHICH group and ID (nPHICHseq) inside the group.
An index number of the PHICH (nPHICHgroup, nPHICHseq) corresponds to a resource position at which the uplink data is transmitted, and specifically, it is determined by a sequence number of the first PRB of corresponding physical uplink shared channel (referred to as PUSCH) data. The PHICHs corresponding to adjacent PRBs may be mapped into different PHICH groups; and a mapping mathematical relationship is:nPHICHgroup=(IPRB_RAlowest_index+nDMRS)mod NPHICHgroup+IPHICHNPHICHgroup,nPHICHseq=(└IPRB_RAlowest_index/NPHICHgroup┘+nDMRS)mod 2NSFPHICH,
where nDMRS represents a cyclic shift indicator index of an uplink data demodulation pilot, IPRB_RAlowest_index represents a minimum physical resource block index allocated by uplink resources, NSFPHICH represents a size of the spreading factor, and NPHICHgroup represents the number of the PHICH groups.
FIG. 1 is a schematic diagram of a baseband processing procedure of PHICH according to the related art; as shown in FIG. 1, one-bit ACK/NACK (0/1) information is processed, using a repeat coding manner, to obtain three-bit coded information, and the 12 symbols are obtained after a BPSK modulation and spreading operation (nPHICHseq)with a coefficient being 4; and the 12 symbols are mapped on the resource position of the three REGs corresponding to the PHICH group (nPHICHseq).
FIG. 2 a schematic diagram of time-frequency domain mapping of PHICH according to the related art; as shown in FIG. 2, in the frequency domain, three REGs corresponding to one PHICH adopts a distributed mapping manner to obtain a diversity gain; while in the time domain, the PHICH has two resource mapping manners, normal and extended. When it is a normal manner, the PHICH is mapped on the first orthogonal frequency division multiplexing (OFDM) symbol of a sub-frame; when the length of a physical downlink control channel (referred to as PDCCH) is 3 (in an MBSFN sub-frame of a hybrid carrier or a time division duplex (TDD) special sub-frame, when the length of the PDCCH is 2), the PHICH may be configured to be an extended PHICH duration; and in this case, the PHICH may be distributed on multiple OFDM symbols which are occupied by the PDCCH.
FIG. 3 is a schematic diagram of a frequency domain initial offset position relationship of different cells of PHICH according to the related art; and as shown in FIG. 3, PHICH resource frequency domain positions of adjacent cells (different Cell IDs) are staggered to each other.
During an LTE-A research stage, many new technologies are introduced, such as coordinated multi-point (referred to as CoMP), carrier aggregation (referred to as CA), and soft cell. In the related art, many new communication scenarios are proposed with regard to these new technologies, wherein in scenarios such as a CoMP scenario 4 and soft cell, the number of users in a single cell is much larger than that in a traditional cell, thus easy to cause the problem of PHICH capacity insufficiency, as well as causing the problems of PHICH collision and interference.
With regard to the problems of PHICH capacity insufficiency, PHICH collision and interference that caused by the number of user in single cell much larger than that in traditional cell in the related technology, no effective solution has been presented.